Using Caché Objects - InterSystems Documentation

You can get detailed information about a specific class definition by opening a
%Dictionary.ClassDefinition object for the class and observing its properties. The ID used to
store %Dictionary.ClassDefinition objects is the class name:
Set cdef = ##class(%Dictionary.ClassDefinition).%OpenId("Sample.Person")
Write cdef.Name,!
// get list of properties
Set count = cdef.Properties.Count()
For i = 1:1:count {
Write cdef.Properties.GetAt(i).Name,!
}
Altering Class Definitions
You can also do this easily from an ActiveX or Java client. Note that you must fully-qualify
class names with their package name or the call to %OpenId will fail.
23.2 Altering Class Definitions
You can modify an existing class definition by opening a %Dictionary.ClassDefinition object,
making the desired changes, and saving it using the %Save method.
You can create a new class by creating a new %Dictionary.ClassDefinition object, filling in its
properties and saving it. When you create %Dictionary.ClassDefinition object you must pass
the name of the class via the %New command. When you want to add a member to the class
(such as a property or method) you must create the corresponding definition class (passing
its %New command a string containing "classname.membername") and add the object to the
appropriate collection within the %Dictionary.ClassDefinition object.
For example:
Set cdef = ##class(%Dictionary.ClassDefinition).%New("MyApp.MyClass")
If %SYSTEM.Status.IsError(cdef) {
Do DecomposeStatus^%apiOBJ(%objlasterror,.Err)
Write !, Err(Err)
}
Set cdef.ClassType = "persistent"
Set cdef.Super = "%Persistent,%Populate"
// add a Name property
Set pdef = ##class(%Dictionary.PropertyDefinition).%New("MyClass:Name")
If %SYSTEM.Status.IsError(pdef) {
Do DecomposeStatus^%apiOBJ(%objlasterror,.Err)
Write !,Err(Err)
}
Do cdef.Properties.Insert(pdef)
Set pdef.Type="%String"
// save the class definition object
Do cdef.%Save()
Using Caché Objects 195